existing underground utilities are identified, use ex-
treme care when working near them. Ripping up utility
lines adds loss time to a project, adds to the cost of the
project, and causes an inconvenience to people to whom
the utilities were supporting.
NOTE: Obtain a digging permit before perform-
ing any excavations on a project.
Symbols for electric power distribution are shown
in figure 15-10. Note the location of these lines not
only for the reasons stated about pipe but also because
of the risk of electric shock when a machine cuts an
NOTE: On some occasions certain items are
mistakenly left out on new drawings. Examples are
buried telephone cables, electrical lines, waterlines,
and fuel lines. Because of this, you must make it a
practice to compare older drawings with new drawings
and to your freehand sketches.
Symbols for building material are shown in figure
15-11. These symbols are used in cross sections or
cutaway views. They also label material as new or
A freehand sketch is a drawing, made without the
use of mechanical aids or devices. Sketches may be
drawn on graph paper, traced, or drawn with a--
straightedge. A sketch may be of an object, an idea, or
a combination of both. The ability to make quick,
accurate sketches is helpful in conveying your ideas
Two examples of freehand sketches are shown in
figures 15-12 and 15-13. These sketches were
Figure 15-11.Material symbols.
Figure 15-10.Electrical power distribution symbols.